Powdermill Nature Reserve Research Articles

Seasonal Amphibian Species Richness and Population Fluctuations at Powdermill Nature Reserve, Pennsylvania, U.S.A.

Amphibians are a highly vulnerable taxonomic group that have suffered population declines worldwide. As amphibians serve critical links between trophic levels and facilitate nutrient recycling, it is critical to understand how their species richness, abundance, and phenology shift over time. Because amphibian populations naturally fluctuate, short-term monitoring can provide insight into how amphibian communities respond to proximate changes in weather conditions, which is helpful for predicting long-term responses to climate change. We used pitfall traps to examine interannual variation of the amphibian community at Powdermill Nature Reserve (PNR) in Pennsylvania during 2020–2021 to provide critical details for future long-term monitoring. Mean monthly temperature and precipitation did not vary significantly between years, but monthly captures per sampling effort declined and monthly biomass per sampling effort increased from 2020 to 2021. Despite a lack of significant relationships between total amphibian captures and temperature and precipitation, peak abundance shifted earlier, and individuals were larger in 2021 compared to 2020. Interestingly, individual species biomass was predicted by an interaction between temperature and precipitation, suggesting individual species will vary in vulnerability to climate change, but the amphibian community as a whole at PNR is resilient to minor fluctuations in temperature and precipitation.

REPEATED SAMPLING OF WILD INDIVIDUALS REVEALS OPHIDIOMYCES OPHIDIICOLA INFECTION DYNAMICS IN A PENNSYLVANIA SNAKE ASSEMBLAGE.

Ophidiomyces ophidiicola is an emerging fungal pathogen associated with infections in snakes across North America. Although documented in Pennsylvania, O. ophidiicola has not been found at Powdermill Nature Reserve (PNR) in southwestern Pennsylvania, where the snake assemblage has been studied since 2002 and several species have recently declined. We surveyed for O. ophidiicola and putative ophidiomycosis at PNR. We screened five species of free-ranging, wild snakes (n=34) for suspected ophidiomycosis by visually checking for dermatitis and swabbing for the presence of O. ophidiicola DNA. We found a moderate prevalence of snakes with skin lesions (n=15) but a low prevalence of snakes with O. ophidiicola DNA in traditional PCR assays (n=2). Both positive snakes belonged to the same species and only one presented with lesions. When quantitative PCR screens were performed on duplicate swabs, 19 snakes were positive for O. ophidiicola DNA, with positive individuals in two species. Mark-recapture methods revealed seasonal variability in disease dynamics for sampled snakes. One individual presented with less than five skin lesions and tested negative in May 2020, had more than five lesions with a high fungal DNA load in June 2020, and no lesions with a low fungal DNA load in July 2020. We also found that snakes sampled from under the same cover object at the same time either all tested positive or all negative, including one instance involving two species. Our results underscore the value of using multiple screening techniques for O. ophidiicola surveillance and repeated sampling of individuals to understand the dynamics of ophidiomycosis in wild populations as compared to single method and single timepoint approaches.

Changes in an Amphibian Community at Powdermill Nature Reserve, Southwest Pennsylvania, Over a 37-Year Period

Historical biodiversity datasets provide invaluable opportunities to examine changes in natural populations, especially with respect to land use and climate change. In 2020, we resurveyed the amphibian community at Powdermill Nature Reserve in Westmoreland County, Pennsylvania, U.S.A. using pitfall traps, replicating surveys that were conducted in 1982–1983. We compared species richness and abundance across the two time periods and examined the potential influence of temperature on capture rates. Species richness was relatively stable, but species composition varied across sampling periods. Most notably, the majority of captures (60.6%) in the 1980s were anurans, and the majority of captures (91.2%) in 2020 were salamanders. Anuran captures peaked earlier in 2020 compared to the 1980s, and salamander captures peaked later in the season, but capture rate was not significantly related to temperature for either group. Shifts in relative abundance should be examined further to determine if these represent temporary or permanent changes.

An annotated set of audio recordings of Eastern North American birds containing frequency, time, and species information.

Acoustic recordings of soundscapes are an important category of audio data that can be useful for answering a variety of questions, and an entire discipline within ecology, dubbed "soundscape ecology," has risen to study them. Bird sound is often the focus of studies of soundscapes due to the ubiquitousness of birds in most terrestrial environments and their high vocal activity. Autonomous acoustic recorders have increased the quantity and availability of recordings of natural soundscapes while mitigating the impact of human observers on community behavior. However, such recordings are of little use without analysis of the sounds they contain. Manual analysis currently stands as the best means of processing this form of data for use in certain applications within soundscape ecology, but it is a laborious task, sometimes requiring many hours of human review to process comparatively few hours of recording. For this reason, few annotated data sets of soundscape recordings are publicly available. Further still, there are no publicly available strongly labeled soundscape recordings of bird sounds that contain information on timing, frequency, and species. Therefore, we present the first data set of strongly labeled bird sound soundscape recordings under free use license. These data were collected in the Northeastern United States at Powdermill Nature Reserve, Rector, Pennsylvania, USA. Recordings encompass 385 minutes of dawn chorus recordings collected by autonomous acoustic recorders between the months of April through July 2018. Recordings were collected in continuous bouts on four days during the study period and contain 48 species and 16,052 annotations. Applications of this data set may be numerous and include the training, validation, and testing of certain advanced machine-learning models that detect or classify bird sounds. There are no copyright or propriety restrictions; please cite this paper when using materials within.

Demography of Aquatic Turtles (Chrysemys picta marginata and Chelydra serpentina serpentina) in Southwestern Pennsylvania

Multi-year studies of syntopic species provide a spatiotemporal framework for comparing their demographic responses to the same environmental conditions. We used data derived from 15 years of sampling at an artificial pond matrix in southwestern Pennsylvania to investigate the survival, growth, and ages of Midland Painted Turtles (Chrysemys picta marginata) and Common Snapping Turtles (Chelydra serpentina serpentina). We trapped turtles with baited hoop-nets at a primary wetland, which was the largest and deepest of five artificial ponds in a spatially aggregated matrix at the Powdermill Nature Reserve, a protected site in the Allegheny Mountains. We captured 81 Midland Painted Turtles 162 times, and 43 Common Snapping Turtles 136 times. For both species, apparent survival probabilities were higher for adults (range 79–95%) compared to juveniles (range 57–82%), and higher in females compared to males or juveniles. The average growth rate was highest in juvenile turtles of both species, indicating growth was maximal during periods of the lowest survival. Average growth rates, in general, were slower for Midland Painted Turtles compared to Common Snapping Turtles. Relating body size to age revealed estimates conforming to studies elsewhere and to longevity records based on known-age turtles. We interpret findings at this wetland matrix to represent the demographics of a deme within a fluid and dynamic regional network of demes for these two species and highlight the value of artificial pond networks to the conservation of freshwater turtle metapopulations in Pennsylvania.

Selection for increased cranial capacity in small mammals during a century of urbanization

Abstract Urbanization is a selective force that is known to drive changes in the population dynamics of wildlife. How animals adapt to changing environmental conditions is crucial to their survival in these environments. Relative brain size, or cranial capacity, is a known proxy of behavioral flexibility, and can be used to assess how well a species has adapted to a particular environment. We examined changes in cranial capacity in a time series of small mammal skulls collected from urban and rural populations in southwestern Pennsylvania. Skulls from urban populations were collected from Allegheny County, an area that experienced rapid urbanization over the past century, and skulls of rural populations from the Powdermill Nature Reserve of the Carnegie Museum, which has remained relatively unchanged forest over the same period. Our results show that Peromyscus leucopus and Microtus pennsylvanicus from urban populations had significantly greater cranial capacity than their rural counterparts, but the opposite was true for Eptesicus fuscus. We found no difference in relative cranial capacity across time in any of the small mammal species. Our results suggest that a larger cranial capacity is selected for in an urban environment and reinforces the hypothesis that behavioral flexibility is important for animals to adapt to novel environments.

Loss of Habitat Leads to Bigger Toads and Bigger Eggs: Natural Area Management Predictions for the Eastern American Toad, Anaxyrus americanus americanus (Holbrook, 1836)

Reproductive characteristics of the Eastern American Toad (Anaxyrus americanus americanus) vary geographically across its broad eastern North American range. Northern populations are known to breed for a shorter period that begins later in the season (April and/or May) than southern populations that can begin in winter and last until April. Delayed maturity and larger minimum body size are also associated with northern populations. Specimens collected during two years of systematic trapping during 1982–1983 at the Powdermill Nature Reserve (PNR), Westmoreland County, Pennsylvania, were examined to test predictions of geographic patterns associated with reproduction and growth of a southwestern Pennsylvania population. The results indicate a short egg laying season in May, large adult body size, and delayed maturity. An apparent response to northern Allegheny climate, the reproductive-related patterns of this population were similar to those of other northern regions rather than populations at similar latitudes within Pennsylvania. Eastern American Toads collected from a breeding site at PNR in 2014 were larger in body size, clutch size, and egg size than those of the 1982–1983 study. Most notably, loss of open breeding habitat in the 30+ years between sampling periods resulted in fewer larger toads producing on average larger eggs and twice the clutch size than counterparts studied during earlier successional series of this study site. These differences quantify geographic and temporal variability in life history traits of an ecologically versatile and geographically widespread species and provide landscape-wide predictions of life history responses by the Eastern American Toad to natural or human-mediated changes to natural areas.

A Survey of Terrestrially Active Salamanders from Two Different Woodlands at the Powdermill Nature Reserve, Pennsylvania

Variation in habitat and microhabitat can affect salamander populations. We systematically surveyed terrestrially active salamanders in an old forest tract and a young forest tract at the Powdermill Nature Reserve in southwestern Pennsylvania during 2009–2011. We examined the effect forest age had on the 2 salamander assemblage structures. While species compositions were similar, assemblage structures were uneven in both the old and young forest sites. Differential use of survey coverboards across species was detected at both sites. This difference in use may be best explained by ground-moisture levels as a function of coverboard distance to water. Counterintuitive findings of low numbers of Desmognathus ochrophaeus (Mountain Dusky Salamander) and Plethodon cinereus (Red-backed Salamander) compared to past studies at these 2 sites appears most likely related to differences in trapping methodology. Patterns of differential use of coverboards and inter-site differences in seasonal activity patterns point to P. glutinosus (Northern Slimy Salamander) as the least restricted species in terms of microhabitat conditions and most seasonally variable in activity.

Augmented Reality Brings the Real World into Natural History Dioramas with Data Visualizations and Bioacoustics at the Carnegie Museum of Natural History

AbstractThis paper introduces the AR Perpetual Garden App and highlights reasons why it is unique and important in its use of immersive, augmented reality for informal learning. The design and construction of the application created a virtual diorama based on facts, using realistic 3D models and accurate perspective. Design affordances permit annotations with interactive and multimodal facts and stories, delivering interactive knowledge artifacts. The app combines real and virtual into one holistic and comprehensive learning experience, transferring scientific knowledge to the novice in an instant. The use of immersive augmented reality produced from accurate information, data visualizations, and bioacoustics creates context‐sensitivity experiences inside the gallery and outside in the gardens. Distribution through the Apple and Google app stores to schools and homes can extend the broader impact of the educational mission of the Carnegie Museum of Natural History and its biological research center, the Powdermill Nature Reserve.

Historic Mining and Agriculture as Indicators of Occurrence and Abundance of Widespread Invasive Plant Species.

Anthropogenic disturbances often change ecological communities and provide opportunities for non-native species invasion. Understanding the impacts of disturbances on species invasion is therefore crucial for invasive species management. We used generalized linear mixed effects models to explore the influence of land-use history and distance to roads on the occurrence and abundance of two invasive plant species (Rosa multiflora and Berberis thunbergii) in a 900-ha deciduous forest in the eastern U.S.A., the Powdermill Nature Reserve. Although much of the reserve has been continuously forested since at least 1939, aerial photos revealed a variety of land-uses since then including agriculture, mining, logging, and development. By 2008, both R. multiflora and B. thunbergii were widespread throughout the reserve (occurring in 24% and 13% of 4417 10-m diameter regularly-placed vegetation plots, respectively) with occurrence and abundance of each varying significantly with land-use history. Rosa multiflora was more likely to occur in historically farmed, mined, logged or developed plots than in plots that remained forested, (log odds of 1.8 to 3.0); Berberis thunbergii was more likely to occur in plots with agricultural, mining, or logging history than in plots without disturbance (log odds of 1.4 to 2.1). Mining, logging, and agriculture increased the probability that R. multiflora had >10% cover while only past agriculture was related to cover of B. thunbergii. Proximity to roads was positively correlated with the occurrence of R. multiflora (a 0.26 increase in the log odds for every 1-m closer) but not B. thunbergii, and roads had no impact on the abundance of either species. Our results indicated that a wide variety of disturbances may aid the introduction of invasive species into new habitats, while high-impact disturbances such as agriculture and mining increase the likelihood of high abundance post-introduction.

Implementation of a sampling strategy to detect West Nile virus in oral and cloacal samples in live song birds

In 1999, West Nile virus (WNV) first appeared in the United States and has subsequently infected more than a million people and untold numbers of wildlife. Though primarily an avian virus, WNV can also infect humans and horses. The current status of WNV and its effects on wildlife in Pennsylvania (PA) is sparsely monitored through sporadic testing of dead birds. In order to acquire a more comprehensive understanding of the status of WNV in wild birds, a study was designed and implemented to sample populations of migratory and local birds at Powdermill Nature Reserve near Rector, PA. Resident and migratory bird species totaling 276 individuals were sampled cloacally and orally to compare the effectiveness of sampling methods. The presence of WNV was tested for using RT-PCR. Two positive samples were found, one from a migrating Tennessee warbler and another from an American robin. The low infection rates indicate that WNV may not be a critical conservation concern in the Westmoreland County region of PA. There was also agreement between oral and cloacal swabs, which provides support for both methods. This study describes a surveillance method that is easily incorporated into any banding operation and which determines the risks of WNV to various bird populations.

Proceedings of the Ninetieth Annual Meeting

The ninetieth annual meeting of the Wilson Ornithological Society (WOS) was held in joint session with the Association of Field Ornithologists (AFO) from Thursday, 9 April, through Sunday, 12 April 2009 at the Hilton Pittsburgh in Pittsburgh, Pennsylvania at the invitation of the National Aviary and Powdermill Nature Reserve, Carnegie Museum of Natural History, in partnership with the Three Rivers Bird Club, Audubon Society of Western Pennsylvania, Duquesne University, University of Pennsylvania, Pennsylvania Game Commission, Western Pennsylvania Conservancy, and the American Birding Association. Todd Katzner, Director of Conservation and Research at the National Aviary, chaired the local committee, which also included Anthony Bledsoe, Jim Bonner, Tammy Colt, Jean Deo, Erin Estell, Mike Kuzemchak, Steven Latta, Andrew Mack, Brady Porter, Brian Shema, Poly Singh, Jack Solomon, Samara Trusso, and James Valimont. The Council met from 0916 to 1708 hrs on Thursday, 9 April, in the Brigade Room of the Hilton Pittsburgh. That evening there was an ‘‘ice-breaker’’ reception for the conferees and guests. The opening session on Friday convened in the Grand Ballroom at 0814 with welcoming remarks from Todd Katzner, WOS President James D. Rising, and AFO President David N. Bonter. After several items of information for the conferees, David Bonter concluded the opening ceremony by introducing the plenary speaker, Bruce Beehler, who delivered a wonderfully thought-provoking presentation, ‘‘The forgotten science—a role for natural history in the 21st Century.’’ The scientific program included 54 contributed papers and 62 contributed posters, which were organized into eight paper sessions, a poster session, and a symposium on remote and automated technologies for monitoring birds. In addition, WOS hosted the Margaret Morse Nice Lecture, presented by the 2009 Nice Medal recipient, Sidney A. Gauthreaux Jr., ‘‘Radar ornithology at different spatial scales.’’ The evening program on Friday included a reception at the National Aviary, which coincided with the poster session. The Three Rivers Bird Club hosted birding forays in the vicinity of the conference site each morning from Thursday through Sunday. In addition, longer trips were scheduled for Sunday to: (1) Powdermill Nature Reserve, the biological research station of Carnegie Museum of Natural History with a trip to Frank Lloyd Wright’s Fallingwater; (2) the Pittsburgh Zoo and view of downtown Pittsburgh from an amphibious tour vehicle; (3) the University of Pittsburgh campus, home of a breeding pair of Peregrine Falcons (Falco peregrinus), and a tour of the Carnegie Museum of Natural History; (4) the Pymatuning Laboratory of Ecology in northwestern Pennsylvania; and (5) Moraine State Park and Lake Arthur. The attendees enjoyed a social hour prior to the annual banquet, which was held in the Kings Garden Room of the Hilton Pittsburgh. The evening festivities included an enjoyable dinner, and afterwards WOS President Rising and AFO President Bonter joined those assembled in thanks to the many persons whose hard work had resulted in a successful conference. President Rising also thanked the three elected members of Council who had completed their terms of office, Carla Dove, Greg H. Farley, and Daniel Klem Jr., and welcomed the three newly elected members of Council, Mary Bomberger Brown, Mary Garvin, and Mark S. Woodrey, who will serve the 2009– 2012 term, and another newly elected member of Council, Mia R. Revels, who will serve the remainder of a vacated 2007–2010 term. The following WOS awards and commendations also were presented:

Variable shifts in spring and autumn migration phenology in North American songbirds associated with climate change

AbstractMonitoring studies find that the timing of spring bird migration has advanced in recent decades, especially in Europe. Results for autumn migration have been mixed. Using data from Powdermill Nature Reserve, a banding station in western Pennsylvania, USA, we report an analysis of migratory timing in 78 songbird species from 1961 to 2006. Spring migration became significantly earlier over the 46‐year period, and autumn migration showed no overall change. There was much variation among species in phenological change, especially in autumn. Change in timing was unrelated to summer range (local vs. northern breeders) or the number of broods per year, but autumn migration became earlier in neotropical migrants and later in short‐distance migrants. The migratory period for many species lengthened because late phases of migration remained unchanged or grew later as early phases became earlier. There was a negative correlation between spring and autumn in long‐term change, and this caused dramatic adjustments in the amount of time between migrations: the intermigratory periods of 10 species increased or decreased by > 15 days. Year‐to‐year changes in timing were correlated with local temperature (detrended) and, in autumn, with a regional climate index (detrended North Atlantic Oscillation). These results illustrate a complex and dynamic annual cycle in songbirds, with responses to climate change differing among species and migration seasons.

Relationships Among Body Mass, Fat, Wing Chord, Age, and Sex for 170 Species of Birds Banded at Powdermill Nature Reserve

Relationships Among Body Mass, Fat, Wing Chord, Age, and Sex for 170 Species of Birds Banded at Powdermill Nature Reserve

Relationships Among Body Mass, Fat, Wing Chord, Age, and Sex for 170 Species of Birds Banded at Powdermill Nature Reserve

Relationships Among Body Mass, Fat, Wing Chord, Age, and Sex for 170 Species of Birds Banded at Powdermill Nature Reserve

Timing and Extent of the Molts of Adult Red-Eyed Vireos on Their Breeding and Wintering Grounds

The molt of adult Red-eyed Vireos (Vireo olivaceus) on their breeding grounds was studied at three widely separated sites in northeastern North America: North Point, James Bay (NPJB), Ontario; Vermont Institute of Natural Science (VINS), Woodstock, Vermont; and Powdermill Nature Reserve (PNR), Rector, Pennsylvania. Unlike other North American vireos and most other North American passerines, adult Red-eyed Vireos undergo an incomplete molt on the breeding grounds. This molt typically replaces most or all of the body plumage, about half of the wing coverts, the tertials, and the central rectrices. Extent of molt did not differ among localities; however, timing of the molt was 1-2 weeks earlier and onset of molt occurred over a longer period at PNR than at VINS or NPJB. Based on examination of museum specimens, flight feathers not molted on the breeding grounds are replaced on the wintering grounds beginning in early January ; average duration of primary molt on the wintering grounds is 78 days. It is unclear whether or not feathers molted on the breeding grounds are molted again at this time. This issue needs to be resolved before Humphrey-Parkes terminology can be applied to breeding and wintering ground molt episodes in this species. Selective advantages associated with a protracted nesting season and with early onset of migration both may have had a role in shaping the molt strategy of adult Red-eyed Vireos. Rapid onset of fall migration following nesting in this seasonally frugivorous species may have been influenced by the phenology of fruit availability and abundance en route to and especially on its Amazonian wintering grounds.

A Possible Relationship between Reversed Sexual Size Dimorphism and Reduced Male Survivorship in the Ruby-Throated Hummingbird

An examination of 28 years of banding data from Powdermill Nature Reserve in southwestern Pennsylvania showed the following trends in the sex ratio (female: male) of Ruby-throated Hummingbirds (Archilochus colubris): 1.1:1 for immature hummingbirds caught in late summer and fall; 1.4:1 for adults in spring (April-May); 3.1:1 for adults in summer (June-7 August); and 4.1:1 for adults in fall (8 August-October). Hypotheses to explain these increasingly female-biased sex ratios include differential migration, capture bias and differential mortality. Banding data from eight other stations in eastern North America provided no evidence of different fall migration routes for males and females. We detected no capture bias at Powdermill, with respect to mesh size of mist nets, net wariness or net avoidance ability, but there was seasonal variation in the number of overlapping captures of males and females at individual mist nets: spring (81.5%); summer (27.6%); fall (44.7%). A capture bias resulting from differences between the sexes in the use of habitats sampled by our mist nets has likely contributed to observed sex ratio variation. Differential mortality, with males suffering greater losses than females, probably also contributed to this variation. Estimated annual survivorship calculated from returns of banded hummingbirds to Powdermill was lower for males (0.294) than females (0.446), but this difference was not significant. The mean minimum known age for returning male hummingbirds at Powdermill was significantly less than that for females; furthermore, the oldest known age for a returning male (three years) was half that observed for a female. The lower inferred survivorship for males may be related to reversed sexual size dimorphism in this species. The body mass of female Ruby-throated Hummingbirds was significantly greater than that of males and did not vary between May and August, whereas males weighed significantly less in June and July than they did in May and August. Low mid-summer mass in males, coupled with increased metabolic demands during the breeding season, may lead to a fatal "energy crisis" in this sex during nocturnal fasting or periods of inclement weather.

A Comparison of Wing Shape between Migratory and Sedentary Dark-Eyed Juncos (Junco hyemalis)

Journal Article A Comparison of Wing Shape between Migratory and Sedentary Dark-Eyed Juncos (Junco hyemalis) Get access Robert S. Mulvihill, Robert S. Mulvihill The Carnegie Museum of Natural History, Powdermill Nature Reserve, Star Route South, Rector, PA 15677 Search for other works by this author on: Oxford Academic Google Scholar C. Ray Chandler C. Ray Chandler Department of Biology, Indiana University, Bloomington, IN 47405 Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 93, Issue 1, 1 February 1991, Pages 172–175, https://doi.org/10.2307/1368620 Published: 01 February 1991 Article history Received: 05 March 1990 Accepted: 18 September 1990 Published: 01 February 1991